1. Field of Invention
This invention relates to substituted polybenzimidazole polymers and processes for their production. More particularly, the invention relates to N-substituted phenyl polybenzimidazole polymers and a process for their production.
2. Prior Art
Polybenzimidazoles are a known class of heterocyclic polymers which are characterized by a high degree of thermal and chemical stability. Processes for their production are disclosed, for example, in U.S. Pat. Re. No. 26,065 and U.S. Pat. Nos. 3,313,783, 3,509,108, 3,555,389, 3,433,772, 3,408,336, 3,549,603, 3,708,439, 4,154,919 and 4,312,976. (All patents enumerated herein are incorporated by reference).
Although polybenzimidazole polymers are generally more resistant to chemical reaction than other types of polymers, such as cellulose acetate polymers, reactions at the imidazole nitrogen-hydrogen bond on the polybenzimidazole polymer will occur under certain conditions, thereby adversely affecting the performance of the polybenzimidazole polymer.
One method of reducing this reactivity is by replacing the imidazole hydrogen with a less reactive substituent to produce a substituted polybenzimidazole polymer. For example, U.S. Pat. No. 4,579,915 discloses a substituted polybenzimidazole polymer wherein the imidazole hydrogen is replaced by an aromatic substituent corresponding to the formula: ##STR1## where R is nitro, cyano or trifluoromethyl and R' is hydrogen, alkyl, nitro, cyano or trifluoromethyl. Although this patent discloses a process for the production of a nitrophenyl polybenzimidazole similar to that produced by this process, it fails to disclose the process of this invention.
U.S. Pat. No. 4,377,546 discloses a phenyl substituted polybenzimidazole polymer. However, this patent also fails to disclose the instant process for production of an N-substituted phenyl polybenzimidazole polymers.
U.S. Pat. No. 3,943,125 discloses a vast array of substituted tetraamino, heterocyclic compounds useful in the preparation of substituted polybenzimidazole polymers. However, the process for production of the substituted polybenzimidazole polymers disclosed in the '125 patent is significantly different from that disclosed in the instant invention.
U.S. Pat. No. 3,518,234 discloses aryl substituted polybenzimidazole polymers, but also fails to disclose the instant process for the production of N-substituted phenyl polybenzimidazole polymers.
U.S. Pat. Nos. 3,578,644 and 4,549,388 disclose processes for the production of hydroxyl modified polybenzimidazoles, but fail to disclose N-substituted phenyl polybenzimidazole polymers or a process for their production.
Accordingly, it is an object of the present invention to prepare N-substituted phenyl polybenzimidazole polymers.
It is a further object of this invention to prepare N-substituted phenyl polybenzimidazole polymers that exhibit a high degree of chemical and thermal stability.
It is a still further object of this invention to prepare N-substituted phenyl polybenzimidazole polymers directly from unsubstituted polybenzimidazole polymers.
It is an additional object of this invention to prepare N-substituted phenyl polybenzimidazole polymers using an alkali hydride to generate polybenzimidazole anions which are subsequently reacted with a substituted phenyl fluoride to generate N-substituted phenyl polybenzimidazole polymers.
These and other objects, as well as the scope, nature and utilization of the process, will be apparent to those skilled in the art from the following description and appended claims.